While any number of devices are known for mixing various substances in liquid, some potential applications for which such devices could be utilized present particular requirements which have not always been adequately addressed by heretofore known mixers. For example, where uniformity of concentration, and thus dispersal, of a substance in a liquid medium, careful control of shear rates in the mixing operation, or where the substance to be dispersed in the liquid presents particular difficulty in wetting, higher degrees of control over dispersal, shear rates, and thorough wetting capability are desirable.
In other applications, it is desirable for such mixers to have a minimum of, or to entirely eliminate, moving parts, to be easily disassembled for maintenance and cleaning, and/or to be capable of operation over a relatively large operating pressure and/or throughput range.
By way of example, it is known that, when utilizing substances, such as polymers, in dry form as a coagulant, flocculent or the like (for example products produced by Allied Colloids Company such as the trademark products Percols 351, E-24, E-10, 155, 156, 721, 728, 753 and 788N), preparation of a concentrated stock solution is desirable to assure proper activation of the polymer in its liquid phase (for example water). It would be desirable therefore, during this polymer dispersion process, for the polymer particles utilized to be prewetted to decrease the dispersion time and prevent the formation of lumps (known as fisheyes) of the polymer material which dissolve very slowly, if at all, due to formation on the outer surface of such lumps of a highly viscous gel which resists passage of liquid necessary for further wetting of the polymer. While the need in various water purification processes for adequate dispersal of polymers in their aqueous phase is recognized, apparatus for achieving such goals have not always proved effective, and further improvement therein could still be utilized.